The present invention relates generally to three-dimensional optical imaging of semi-transparent and opaque objects and more particularly to three-dimensional optical imaging of semi-transparent and opaque objects using ultrashort light pulses, a streak camera and a coherent optical fiber bundle.
In conventional photography, 2 dimensional (2-dim) images are obtained from three-dimensional (3-dim) objects. In holography, 3 dimensional (3-dim) as opposed to 2-dim images have been produced from 3-dim objects. A framing camera takes a sequence of images over a time interval. However, holography and framing cameras have intrinsic problems which prevent their usage in situations where high spatial resolution images are to be displayed.
In holography, 3-dim images are obtained from the interference of light waves. In order to record an undistorted holographic image, the spatial resolution of the holographic recording material should be better than 1000 lines/mm. This spatial resolution requirement cannot be met with the current electronic video technology wherein the spatial resolution is about 100 lines/mm.
A framing camera produces a series of frames. The series of frames do not constitute a continuous image. A framing camera having an electronic type of time shutter is limited to from about hundreds of picoseconds per frame to about hundreds of nanoseconds per frame. The shutter time from the fastest framing camera will transfer to a few centimeter image spatial resolution which is not satisfactory for high quality image recording and displaying. A framing camera having an optical Kerr shutter requires multiple shots to segment multiple planes of a 3-D object.
Thus, the need clearly exists for a new and improved technique for making 3-dim images of 3-dim objects and, in particular, for making 3-dim images corresponding to surface shape and inner structure of 3-dim semi-transparent objects or the surface shape of 3-dim opaque objects.
The following is a list of known references:
T. A. Shankoff, Applied Optics 7 2101 (1968) PA0 H. Smith "Holographic Recording Materials", Springer Verlag, N.Y. (1978) PA0 T. Y. Yang, P. P. Ho, A. Katz, R. Alfano, R. Ferrante, Applied Opt. 24 2021 (1985) PA0 P. Ho, "Ultrafast Kerr Gate" ch. 25, in "Ultrafast Processes in Semiconductors" ed. by R. Alfano, Academic Press, New York (1984) PA0 Y. Takiguchi, K. Kinoshita, M. Suyama, Y. Inagaki, and Y. Tsuchiya, SPIE Proceeding volume 693 pp. 105-110 (1986) PA0 Y. Takiguchi, S. Aoshima, and Y. Tsuchiya, SPIE Proceeding v. 693 pp. 118-124 (1986)
It is an object of this invention to provide a new and improved technique for producing a 3-dim image of a 3-dim semi-transparent object or a 3-dim opaque object.
It is another object of this invention to provide a technique for converting a 1-dim image into a 3-dim image.
It is still another object of this invention to provide a technique for converting a streak camera into the equivalent of a framing camera that is continuous in time.